CdSe thin films have been grown on GaAs (0 0 1) substrates by molecular beam epitaxy (MBE). The effects of substrate temperature and annealing treatment on the structural properties of CdSe layers were investigated. The growth rate slightly decreases due to the accelerated desorption of Cd from CdSe surface with an increase in the temperature. The sample grown at 260 degrees C shows a polycrystalline structure with rough surface. As the temperature increases over 300 degrees C, crystalline CdSe (0 0 1) epilayers with zinc-blende structure are achieved and the structural quality is improved remarkably. The epilayer grown at 340 degrees C displays the narrowest full-width at half-maximum (FWHM) from (0 0 4) reflection in double-crystal Xray rocking curve (DCXRC) and the smallest root-mean-square (RMS) roughness of 0.816 nm. Additionally, samples fabricated at 320 degrees C were annealed in air for 30 min to study the films' thermal stability. X-ray diffraction (XRD) results indicate that the zinc-blende structure remains unchanged when the annealing temperature is elevated to 460 degrees C, meaning a good thermal stability of the cubic CdSe epilayers. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.